(CBS) YAKIMA, Wash.-- The disappearance of Jay Sloop, a 77-year-old retired doctor from Washington State who went missing in Ukraine two weeks ago, has been classified as a criminal case, according to Sloop's family and officials from his church, reported the Yakima Herald-Republic.

The paper said Sloop disappeared May 14 when he left a church compound in Kiev, the capital of Ukraine, to go for a stroll. He was there to establish a lifestyle center with other medical professionals for the Seventh-day Adventist Church.

Jay Wintermeyer, a spokesman for the church, told the Herald-Republic that police in Kiev have officially classified Sloop's disappearance as a criminal case.

"So far there are really no leads that we have from our investigators (and) people that we've been working with. The police may have some leads we don't know about. But at this point, the park idea has been excluded. (It's been) searched with dogs twice - repeated searches from top to bottom. He really cannot be in the park," said one of Sloop's three sons who is a neurologist, Dr. Richard Sloop.

He said he didn't think his father disappeared due to a medical problem, reported the paper.

"The U.S. Embassy has said (this disappearance) is extremely rare. It seems very difficult to imagine that he could just get lost, slip and fall, those kinds of things. I think it's likely there's some kind of criminal element here. What the motivation would be would just be wild speculation," he continued.

Jay Sloop, a retired obstetrician, is the director at the Upper Columbia Conference Health Ministries in Spokane, Washington. He had an OB/GYN practice in Yakima, about 140 miles southeast of Seattle, from 1969-2005, the Herald-Republic reported.

Another one of Sloop's sons, Greg Sloop, of Portland, Ore. created a blog which he has been updating regularly about the status of his father's case. On Saturday night, according to the paper, he wrote:

"No great news - we still have not found Dad.

"We followed up some reported sightings and spent some time walking areas around the place we know where Dad last was. There were some other things done - but that's the general feel of it. ... This is really, totally and completely in God's hands. Realizing we are powerless and that God is the one in control is hard - but it's clear we're not going to solve this ourselves. So, we keep asking for his intervention, and to help us realize his direction and the will to follow where he leads."